EFFECT OF DIAGONAL ENERGY DISORDER ON CIRCULAR-DICHROISM SPECTRA OF FENNA-MATTHEWS-OLSON TRIMERS

Circular dichroism spectra of Fenna-Matthews-Olson trimers (bacterioch lorophyll a-protein antenna complexes from green photosynthetic bacter ia) are unusually sensitive to diagonal energy disorder because the re sonance interactions between pigments belonging to different protein s ubunits are weak (less than or equal to 20 cm(-1)). Substantial differ ences occur between CD spectra in exciton simulations performed with a nd without realistic inhomogeneous distribution functions for the inpu t pigment diagonal energies. Future simulations of FMO optical propert ies such as CD and pump-probe anisotropies should consider diagonal di sorder in order to accurately describe this antenna's electronic struc ture.